Field of the Invention
The present invention relates generally to vehicles for transporting mined ore and the like in and around underground mines, and more particularly, to a battery-powered mineral hauler or utility vehicle including AC driven traction and pump motors.
Mined payloads typically are transported through the tunnels of underground mines either by a railway train, including a locomotive and one or more cars operating on a fixed system or railway tracks, or by rigid body, load-carrying trucks, such as wheeled dump trucks, that are designed for hauling loads over paths in underground mine tunnels. Some rigid body, load-carrying trucks are powered by diesel powered generators. However, diesel powered vehicles are relatively expensive to operate because of fuel costs. Consequently, mined payload hauling vehicles typically are operated by electrical power that is supplied to the vehicle via tether cables.
Tethered mining vehicles are commercially available from Joy Mining Machinery, Warrendale Pa., for example. Such commercially available mining machines include AC trams used in conjunction with an AC 3-phase power source, typically operating at 500 VAC to 1000 VAC, with electrical power being supplied to the machine via a power cable. However, the need for power cables limits the distance that the vehicle can travel as well as the maneuverability of the vehicle. For example, tethered vehicles must run detailed routes so as not to get crossed up with other cabled vehicles operating in the same mine installation.
To avoid some of the shortcomings associated with the use of power cables, other prior art mineral haulers use a battery as a primary power source. For example, battery-powered coal haulers available from Joy Mining Machinery use DC motors and DC chopper drives. All battery powered mineral hauling vehicles known to applicant employ DC motors. Although the use of a battery as a primary power source obviates the need for a power cable, the DC motors require carbon brushes that are subject to carbon tracking and premature failure.
The automotive industry is looking into hybrid cars that use both a battery and an internal combustion engine for power, but these hybrid vehicles are not designed for use in mining applications.
It is accordingly the primary objective of the present invention that it provide an improved utility vehicle or mineral hauler for use in transporting payloads including mined materials, supplies and other loads, through the tunnels of underground mines.
Another objective of the present invention is that it provide a utility vehicle or mineral hauler that employs AC driven traction and pump motors.
A further objective of the present invention is that it provide a utility vehicle or mineral hauler that employs AC driven traction and hydraulic pump motors that derive electrical power from a battery carried by the vehicle.
The utility vehicle or mineral hauler of the present invention must also be of construction which is both durable and long lasting, and it should also require little or no maintenance to be provided by the user throughout its operating lifetime. In order to enhance the market appeal of the utility vehicle or mineral hauler of the present invention, it should also be of inexpensive construction to thereby afford it the broadest possible market. Finally, it is also an objective that all of the aforesaid advantages and objectives be achieved without incurring any substantial relative disadvantage.